Engineering topics

Johnson, James W.

Publications and source records attributed to Johnson, James W..

3 records

NASA NTRS2001

Feasibility Study of Radiometry for Airborne Detection of Aviation Hazards

Radiometric sensors for aviation hazards have the potential for widespread and inexpensive deployment on aircraft. This report contains discussions of three aviation hazards - icing, turbulence, and volcanic ash - as well as candidate radiometric detection techniques for each hazard. Dual-polarization microwave radiometry is the only viable radiometric technique for detection of icing conditions, but more research will be required to assess its usefulness to the aviation community. Passive infrared techniques are being developed for detection of turbulence and volcanic ash by researchers in this country and also in Australia. Further investigation of the infrared airborne radiometric hazard detection approaches will also be required in order to develop reliable detection/discrimination techniques. This report includes a description of a commercial hyperspectral imager for investigating the infrared detection techniques for turbulence and volcanic ash.

Gimmestad, Gary G.↗

NASA NTRS1990

Space Station Freedom: Dynamic instrumentation for a large space structure

A proposed approach called Modal Identification Experiment (MIE) for obtaining on-orbit dynamic response measurements on Space Station Freedom, the first of a family of large, flexible space structures is discussed. The Phase 2 conceptual design study which provides a conceptual design of a proposed measurement system and an experimental protocol for inobstrusively collecting dynamic response data critical to characterizing important vibration modes of Space Station Freedom were recently concluded. The case for conducting such a measurement program is presented and the specific MIE objectives that were identified, are listed. The sequence of discrete Space Station Freedom assembly configurations is described, and the Phase 2 conceptual design of the experiment and instrumentation system are defined. In addition, a plan to utilize a space station hydrid scale model in laboratory simulations as part of the design process are discussed.

Raney, John P.↗

NASA NTRS1988

The Space Station structural characterization experiment

A space flight experiment being developed by NASA's Office of Aeronautics and Space Technology (OAST) that uses the Space Station as a testbed to study techniques for determining the dynamic characteristics of large space structures (LSS) is described. The experiment is separate from the Space Station Program itself with research objectives outside the domain of Space Station Program objectives. A brief description of the experiment, in terms of the general objective and approach, is given along with a statement of the potential benefits to NASA and others. The bulk of material to follow deals with the experiment definition activity that is underway. The scope of an 'initial' definition study and preliminary results from supporting Space Station dynamics analyses is presented. The term initial is used to indicate that the study currently being conducted has limited objectives and is not expected to complete the required experiment definition. A follow on study is planned and is mentioned in the summary.

Johnson, James W.↗